Thermochromic writing implements

Abstract

To provide a thermochromic writing instrument which prevents a friction body from being soiled when not in use.SOLUTION: A writing body 3 is housed inside a barrel 2 so as to be movable in the front-rear direction. A thermochromic ink is housed inside the writing body 3. A pen tip capable of ejecting the thermochromic ink is provided in the writing body 3. A side wall 29 of the barrel 2 projects a first operating body that can move in the front-rear direction. By sliding the first operating body 4 forward, the pen tip of the writing body 3 can be retracted from a front end hole 27 of the barrel. A friction body 6 capable of thermally discoloring handwriting of the thermochromic ink by frictional heat is housed inside the barrel 2. At the rear of the writing body 3, at least a part thereof projects from the rear end of the barrel 2, and a second operating body 5 capable of operating the first operating body 4 is provided. The second operating body 5 is provided with the friction body 6 at its front portion, and is detachably attached to the barrel 2 so as to be slidable back and forth along the axial direction by magnetic force.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a thermochromic writing instrument. Specifically, a writing body is accommodated in a shaft cylinder so as to be movable in the front-rear direction, and by sliding an operating body forward, the pen tip of the writing body is configured to be able to protrude from and retract into the front end hole of the shaft cylinder. The present invention relates to a thermochromic writing instrument provided with a friction body in the shaft cylinder that rubs the writing of the thermochromic ink and can thermochromically change the writing with the frictional heat generated at that time.

Background Art

[0002] Conventionally, in Patent Document 1, in a thermochromic writing instrument, a writing body containing thermochromic ink is accommodated in a shaft cylinder, and the operating body provided on the shaft cylinder is operated to move the writing body in the front-rear direction, and the pen tip of the writing body is configured to be able to protrude from and retract into the tip of the writing instrument. A thermochromic writing instrument provided with a friction part that can thermochromically change the writing of the thermochromic ink with the frictional heat generated at that time, and a clip body as at least one of the operating bodies. The friction part is provided at the rear end of the shaft cylinder, and the clip body is provided at a part of the shaft cylinder other than the rear end.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The thermochromic writing instrument described in Patent Document 1 has a friction element that is always exposed to the outside. Therefore, when not in use, the user's fingertips may come into contact with the friction element, or when the thermochromic writing instrument is stored in a container (e.g., a pen case, pen holder, or clothing pocket), the friction element may come into contact with the inner surface of the container (e.g., the inner surface of a pen case, the bottom surface of a pen holder, or the inner surface of a clothing pocket), causing fingerprints, dust, etc. to adhere to the surface of the friction element, resulting in dirt on the surface of the friction element. Furthermore, when the paper surface is rubbed using the dirty friction element, the paper surface becomes dirty.

[0005] The present invention aims to solve the aforementioned problems of the conventional method and to provide a thermochromic writing instrument that can prevent the friction material from becoming soiled when not in use.

[0006] In this invention, "front" refers to the pen tip side, and "back" refers to the opposite side, the friction body side. [Means for solving the problem]

[0007] The present invention relates to a thermochromic writing instrument comprising: a writing body movably housed inside a barrel; thermochromic ink housed inside the writing body; a pen tip from which the thermochromic ink can be dispensed provided at the front end of the writing body; a first operating body movably housed inside the side wall of the barrel; the pen tip of the writing body retracting from a front end hole of the barrel by sliding the first operating body forward; and a friction body made of a low-wear elastic material capable of thermochromic discoloring the writing by friction with the writing of the thermochromic ink, thereby generating frictional heat. The thermochromic writing instrument further comprises a second operating body at the rear of the writing body, at least a portion of which protrudes from the rear end of the barrel and capable of operating the first operating body, the second operating body having the friction body at its front and being slidably and detachably mounted to the barrel by magnetic force along the axial direction.

[0008] According to the thermochromic writing instrument of the present invention, a friction body is provided at the front of the second operating body, and the friction body is housed inside the barrel. Therefore, regardless of whether the pen tip is extended or retracted, contact with the user's fingertips and contact between the friction body and the inner surface of the housing (for example, the inner surface of a pen case, the bottom surface of a pen stand, or the inner surface of a clothing pocket) can be avoided, and fingerprints, dust, etc. can be prevented from adhering to the friction body (i.e., the friction body becomes dirty). Furthermore, since the second operating body is magnetically attached to the barrel, there is no need for a locking or press-fitting structure to the barrel, and the second operating body is automatically attracted to the barrel by magnetic force simply by bringing it close to the barrel. Therefore, the second operating body can be easily attached to and detached from the barrel. Furthermore, since the second operating body is equipped with a friction element at its front, the friction element can be easily exposed to the outside by removing the second operating body from the barrel. This prevents the friction element from being soiled with fingerprints or oil by gripping the operating body, and the firm grip makes it easier to apply force when performing the rubbing motion with the friction element to cause thermal discoloration of the writing due to frictional heat.

[0009] Furthermore, in the thermochromic writing instrument of the present invention, the first operating body can be indirectly operated by operating the second operating body that protrudes from the rear end of the barrel, causing the tip of the writing instrument to protrude from the front end hole of the barrel. The user can choose to operate either the first operating body that protrudes from the side wall of the barrel or the second operating body that protrudes from the rear end of the barrel to extend the writing instrument, thus providing high convenience.

[0010] Furthermore, in the present invention, the elastic material constituting the friction body is preferably an elastic synthetic resin (rubber, elastomer), such as silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butadiene-styrene copolymer), fluororesin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM), etc. The elastic synthetic resin constituting the friction body 4 is not a highly abrasive elastic material (for example, an eraser), but a low-abrasive elastic material that produces almost no wear debris (eraser shavings) during friction.

[0011] Furthermore, either the barrel or the second operating body may be equipped with a magnet, and the other may be equipped with a ferromagnetic material that magnetically attaches to the magnet. In this case, the ferromagnetic material on the other is attracted by the magnetic field generated by the magnet on either the barrel or the second operating body, so that the second operating body can be magnetically attracted to the barrel without using press-fitting or locking structures. When the second operating body is magnetically attached to the barrel, it is preferable to adjust the magnetic force, magnetic field, shape, and distance between the magnet and the ferromagnetic material so that the axial position of the second operating body relative to the barrel is stable. This prevents the pen tip from being accidentally extended by the second operating body pushing the first operating body forward when the second operating body is attached to the barrel.

[0012] In this invention, a ferromagnetic material refers to a substance that is attracted by the magnetic force of a magnet, is strongly magnetized by a magnetic field, and retains its magnetization even after the magnetic field is removed. Examples include iron, cobalt, nickel and their alloys, and ferrite.

[0013] Furthermore, the first operating body may be operated by operating the second operating body, and when the distance between the magnet and the ferromagnetic material is maximized as the second operating body moves forward, the operating body may be configured to return to its original position solely by the magnetic force acting between the magnet and the ferromagnetic material. In this case, even if the second operating body is moved forward by a pressing motion, the magnetic force will return the second operating body to its original position, eliminating the need to bias the second operating body with a compression spring such as a coil spring, thus simplifying the configuration of the operating mechanism and reducing costs. In addition, since the second operating body always returns to its original position even when the writing tip is extended, it does not become retracted into the barrel when the second operating body is removed from the barrel to use the friction element, thus preventing the second operating body from becoming difficult to grip.

[0014] Furthermore, when the second operating body is removed from the barrel, it may be configured to be magnetically detachable from the barrel even if the front-to-back direction of the second operating body is reversed. In this case, the friction body locked to the second operating body is configured to protrude rearward from the rear end of the barrel, which prevents the removed second operating body from being lost or damaged. Additionally, since the barrel can be gripped and operated when the ink is thermally discolored using the friction body, it is preferable to grip a barrel that is at least thicker than the second operating body to ensure a firm grip and make it easier to apply force.

[0015] Furthermore, when the second operating body is mounted on the shaft cylinder in reverse, the second operating body may be configured to come into contact with a restricting portion that restricts the forward movement of the operating body. In this case, even when force is applied when using the friction body, it is possible to prevent the friction body from moving forward and sinking into the shaft cylinder together with the second operating body, thus allowing more force to be applied when using the friction body and facilitating friction action. [Effects of the Invention]

[0016] The thermochromic writing instrument of the present invention can prevent the friction element from becoming soiled when not in use. [Brief explanation of the drawing]

[0017] [Figure 1] This is a longitudinal cross-sectional view showing a thermochromic writing instrument in a state of non-use according to one embodiment of the present invention. [Figure 2] This is an enlarged end view of line AA in Figure 1. [Figure 3] This is an exploded view of the second operating unit. [Figure 4] This is a longitudinal cross-sectional view of the state after the second operating body has been moved forward from the state shown in Figure 1. [Figure 5] This is a vertical end view of one embodiment of the present invention during use, showing the state in which the second operating body has retracted from the state shown in Figure 4. [Figure 6] This is an explanatory diagram illustrating the state after removing the second operating unit from the state shown in Figure 1. [Figure 7]It is a longitudinal end view showing the state where the second operating body is removed from the state of FIG. 1 and the second operating body is attached in the reverse front-back direction.

Embodiments for Carrying out the Invention

[0018] Embodiments of the present invention are shown in FIGS. 1 to 7. FIG. 1 is a longitudinal sectional view showing a non-use state of a thermochromic writing instrument in one embodiment of the present invention, FIG. 2 is an enlarged end view taken along line A-A of FIG. 1, FIG. 3 is an exploded view of the second operating body of this embodiment, FIG. 4 is a longitudinal sectional view in a state where the second operating body is advanced from the state of FIG. 1, FIG. 5 is a longitudinal end view during use of one embodiment of the present invention, FIG. 6 is a view showing a state where the second operating body has retreated from the state of FIG. 4, FIG. 6 is an explanatory view for explaining a state where the second operating body is removed from the state of FIG. 1, and FIG. 7 is a longitudinal end view showing a state where the second operating body is removed from the state of FIG. 1 and the second operating body is attached in the reverse front-back direction.

[0019] The thermochromic writing instrument 1 of this embodiment includes a shaft cylinder 2, a writing body 3 housed in the shaft cylinder 2, a first operating body 4 protruding radially outward from the outer surface of the shaft cylinder 2, and an emerging and disappearing mechanism that allows the pen tip 31 of the writing body 3 to emerge and disappear from the front end hole 27 of the shaft cylinder 2 by sliding the first operating part 4 forward.

[0020] The writing body 3 includes a pen tip 31, an ink storage tube 32 in which the pen tip 31 is press-fitted and fixed to the front end opening, thermochromic ink filled in the ink storage tube 32, and a follower (for example, a high-viscosity fluid) filled at the rear end of the thermochromic ink and advancing as the thermochromic ink is consumed.

[0021] The pen tip 31 may consist of, for example, a metal ballpoint pen tip that rotatably holds a ball at its front end, or a synthetic resin pen tip holder that holds the rear outer surface of the ballpoint pen tip. A tail plug 33 with a vent hole that allows air to pass between the ink reservoir 32 and the outside is attached to the rear end opening of the ink reservoir 32. Inside the pen tip 31 is a spring that presses the ball at the front end forward. The spring is a compression coil spring with a rod portion at its front end, and the front end of the rod portion is in contact with the rear surface of the ball. When not writing, the forward biasing force of the spring causes the ball to be in close contact with the inner surface of the inwardly facing front edge of the front end of the ballpoint pen tip, preventing ink leakage and evaporation from the front end of the pen tip 31.

[0022] The shaft cylinder 2 consists of a tapered cylindrical front shaft 21, a cylindrical middle shaft 22 screwed to the rear of the front shaft, and a cylindrical rear shaft 23 connected to the rear end of the middle shaft 22. A slide hole 24 extending in the front-rear direction and penetrating in the radial direction is formed in the rear side wall 29 of the shaft cylinder 2 (side walls of the middle shaft 22 and the rear shaft 23). A cam portion 26 is integrally formed on the inner surface of the shaft cylinder 2 (middle shaft 22), and a stepped regulating portion 28 that protrudes inward is formed on the inner surface of the rear shaft 23 behind the cam portion 26.

[0023] A rear end opening 25 is formed at the rear end of the shaft cylinder 2 (the rear end of the rear shaft 23). A cylindrical body 9 made of a ferromagnetic material is press-fitted or fitted over the rear end opening 25. This fixes the cylindrical body 9 to the shaft cylinder 2, forming a mounting opening 10 consisting of the cylindrical body 9 and the inner circumference of the rear shaft 23. A second operating body 5, described later, is mounted in the mounting opening 10 so as to be slidable and detachable in the forward and backward directions.

[0024] The first operating body 4 comprises an operating portion 41 protruding outward from the slide hole 24 of the shaft cylinder 2, a base portion 42 integrally connected to the operating portion 41, a shaft portion 43 integrally connected to the base portion 42 and extending forward from the base portion 42, and a rear hole 44 extending forward from the rear end of the base portion 42. The first operating body 4 is obtained from a molded body of synthetic resin (for example, polycarbonate resin). Cam teeth that engage with the rotating member 7 are formed at the front end of the shaft portion 43, either integrally or by attachment of a separate member. A friction body 6, described later, is formed in the rear hole 44 so as to be insertable, and the front end of the friction body 6 abuts against the bottom portion 45 of the rear hole 44.

[0025] The second operating body 5 has a cylindrical operating body 51 and a tail cap 52 that is press-fitted or overlap-fitted to the rear inner circumference 55 of the operating body 51. A friction body 6 made of an elastic material is locked to the front inner circumference 53 of the operating body 51 by press-fitting or overlap-fitting. The friction body 6 protrudes forward from the front end of the second operating body 5, and a protruding portion 61 of the friction body 6 is formed in front of the second operating body 5, with the top of the protruding portion 61 formed in a convex curved shape. Furthermore, a rear section 56 is formed at the rear of the second operating body 5 (tail cap 52) that can come into contact with the restricting portion 28 of the shaft cylinder 2 when the second operating body 5 is mounted on the shaft cylinder 2 in reverse.

[0026] A magnet 8, made of a permanent magnet, is press-fitted or over-fitted into the central inner circumference 54 of the second operating body 5 (operating body 51). The axial length of the magnet 8 is formed to be approximately the same as the axial length of the cylindrical body 9 (ferromagnetic material). Furthermore, as shown in Figure 2, the magnet 8 in this embodiment is formed such that one half is an N pole 81 and the other half is an S pole 82 when viewed from the cross-sectional direction. As a result, the magnet 8 generates a strong magnetic field in the direction of the arrow in Figure 2.

[0027] As described above, the second operating body 5 is detachably and slidably mounted in the mounting opening 10 of the shaft cylinder 2 along the axial direction. When mounted, the second operating body 5 is attracted to the cylindrical body 9 (ferromagnetic material) by the magnetic force of the magnet 8. At this time, the magnetic force of the magnet 8 acts strongly in the axial direction, as indicated by the arrow in Figure 2, and the axial lengths of the magnet 8 and the cylindrical body 9 (ferromagnetic material) are formed to be approximately the same length. As a result, the magnet 8 is stably fixed by magnetic force at approximately the same position as the cylindrical body 9 (ferromagnetic material) in the axial direction. At this time, the friction body 6, which is locked to the second operating body 5, is inserted into the rear hole 44 of the first operating body 4, and the front end of the friction body 6 abuts against the bottom 45. The rear end of the second operating body 5 protrudes rearward from the rear end opening 25 of the shaft cylinder 2. Therefore, by pushing the second operating body 5 forward, the first operating body 4 can be pushed forward.

[0028] The aforementioned retractable mechanism is a side-slide type retractable mechanism using a rotating cam mechanism. The retractable mechanism consists of a cam portion 26 formed on the inner surface of the rear shaft 23, a rotating member 7 that engages with the cam portion 26 and abuts against the rear end of the writing body 3, a first operating body 4 that engages with the rotating member 7 and protrudes radially outward from the slide hole 24, a second operating body 5 that protrudes rearward from the rear end opening 25 of the barrel 2, and a resilient body 11 (for example, a compression coil spring) housed inside the barrel 2 and biasing the writing body 3 rearward. In this embodiment, the retractable mechanism is a double-knock type in which both the pen tip extension operation and the pen tip retraction operation are performed by sliding the first operating body 4 forward or pressing the second operating body 5 forward.

[0029] When the second operating body 5 is pressed forward against the magnetic force of the magnet 8 and the backward biasing force of the elastic body 11 from the pen tip retracted state shown in Figure 1, the first operating body 4, which is in contact with the friction body 6, is pressed forward, and the rotating member 7 is pressed forward by the first operating body 4, which in turn presses the rear end of the writing body 3 forward, causing the pen tip 31 to protrude forward and outward from the front end hole 27. At this time, the rotating member 7 engages with the cam portion 26, and the pen tip is maintained in the state shown in Figure 4. Then, the second operating body 5 is attracted to the cylindrical body (ferromagnetic material) by the magnetic force of the magnet 8 and retracts to its position before being pressed, resulting in the state shown in Figure 5. As a result, the thermochromic writing instrument 1 becomes usable (ready to write).

[0030] Next, when the second operating unit 5 is pressed forward against the magnetic force of the magnet 8 from the pen tip protruding state shown in Figure 5, the front end of the friction body 6 fixed to the advanced second operating unit 5 comes into contact with the bottom of the first operating unit 4, causing the first operating unit 4 to move forward. Then, the advanced first operating unit 4 moves the rotating member 7 forward, disengaging the cam portion 26 from the rotating cam of the rotating member 7, causing the rotating member 7 to move backward. Consequently, the writing body 3, the first operating unit 4, and the second operating unit 5 move backward, resulting in the pen tip being retracted. As a result, the thermochromic writing instrument 1 is in a non-use state (non-writing state and non-friction body state). Furthermore, when the writing body 3, the first operating body 4, and the second operating body 5 move backward, the second operating body 5 is attracted to the cylindrical body 9 (ferromagnetic material) by the magnetic force of the magnet 8, stopping its backward movement. This reduces the impact force generated when the backward movement stops, and the first operating body is absorbed by the friction body 6, which is made of an elastic material and fixed to the second operating body 5. As a result, the impact force on the writing body 3 is reduced. This is particularly effective in a structure like this embodiment, where a ball is enclosed in the pen tip of the writing body 3. When the writing body 3 moves backward, if it receives a strong impact, the ball may move backward, drawing air between the ball and the tip of the ballpoint pen, which may hinder the ejection of ink during writing.

[0031] Furthermore, the forward extension and retraction of the cursive writing tip 3 can also be performed by sliding only the first operating part 4 forward, without the need to operate the second operating part 5. Therefore, the user can extend the cursive writing tip and transition from the unused state to the used state by operating either the first operating part 4 or the second operating part 5, making it highly convenient.

[0032] Next, the process of removing the second operating body from the barrel 2 and reattaching it will be described. In this embodiment, the thermochromic writing instrument 1 can be removed from the barrel 2 as shown in Figure 6 by grasping the second operating body 5 and pulling it backward against the magnetic force acting between the magnet 8 and the cylindrical body 9 (ferromagnetic material) from the state shown in Figure 1. At this time, the friction body 6 is pulled out together with the second operating body 5 and exposed to the outside, so the second operating body 5 can be firmly gripped as it becomes the gripping part, and frictional heat is generated by rubbing the writing made with thermochromic ink of the writing instrument with the friction body 6, causing the writing to change color. Furthermore, when the removed second operating body 5 is brought close to the mounting opening 10 of the barrel away from the friction body 6, the magnetic force of the magnet 8 pulls the second operating body 5 into the barrel and it is attracted to the original position shown in Figure 1.

[0033] Furthermore, in this embodiment, when reattaching the second operating body 5 to the shaft 2 from the state in which it has been pulled out as shown in Figure 6, the second operating body 5 can be attached to the shaft 2 even if its front-to-back direction is reversed. When the front-to-back direction of the second operating body 5 is reversed and brought close to the mounting opening 10 of the shaft 2 from the rear end side, the second operating body 5 is attracted to the cylindrical body 9 (ferromagnetic material) by the magnetic force of the magnet 8, similar to when it is attached from the friction body 6 side, and is attached to the shaft 2 as shown in Figure 7. In this state shown in Figure 7, the regulating portion 28 of the shaft and the rear part 56 of the second operating body 5 are in contact, and the friction body 6 protrudes rearward from the rear end opening 25 of the shaft 2, and the second operating body 5 is attached to the shaft 2. Therefore, when rubbing the ink markings with the thermochromic ink with the friction body 6 in the state shown in Figure 7, the barrel 2 can be gripped and the rubbing action performed can be carried out. Since the barrel 2 has a larger diameter than the second operating body 5, it is easier to apply force than when gripping the second operating body 5 and performing the rubbing action. Furthermore, the rubbing action can be carried out easily, and the ink markings can be thermally discolored by frictional heat. Moreover, in this embodiment, even when the second operating body 5 is mounted in reverse, the pen tip 31 of the writing body 3 can be extended and retracted by sliding the first operating body 4 along the axial direction, thus further improving convenience.

[0034] In this embodiment, the elastic material constituting the friction body 6 is preferably an elastic synthetic resin (rubber, elastomer), such as silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butadiene-styrene copolymer), fluororesin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM), etc. The elastic synthetic resin constituting the friction body 6 is not a highly abrasive elastic material (for example, an eraser), but a low-abrasion elastic material that produces almost no wear debris (eraser residue) during friction. Furthermore, the friction body 6 only needs to be provided on the outer surface of the front end of the second operating body 5, for example, a configuration in which the friction body 6 made of an elastic material is locked (fixed) to the outer surface of the front end of the second operating body 5 by press-fitting, engagement, screwing, fitting, bonding, two-color molding, etc., or a configuration in which the entire second operating body 5 other than the magnet 8 is integrally formed from an elastic material.

[0035] In this embodiment, the material constituting the cylindrical body 9 (ferromagnetic material) is attracted by the magnetic force of the magnet 8, and it is preferable to use a material that is strongly magnetized by a magnetic field and retains its magnetization even after the magnetic field is removed. Examples include iron, cobalt, nickel and their alloys, ferrite, etc.

[0036] In this embodiment, the thermochromic writing instrument 1 has high convenience because the friction element 6 can be stored inside the barrel 2 when not needed, and both the friction element 6 and the second operating element 5, which is attracted by magnetic force, can be easily removed from the barrel to perform the friction action, thereby preventing the friction element 6 from becoming dirty. [Explanation of symbols]

[0037] 1. Thermochromic writing instruments 2 shaft cylinder 21 Front axle 22 Center axis 23 rear axle 24 slide holes 25 Rear end opening 26 Cam section 27 Front end hole 28 Regulatory Department 29 Rear side wall (side wall) 3 Cursive 31 nibs 32 Ink storage tubes 33. Tail plug 4 1st operating body 41 Operation section 42 Base 43 Shaft section 44 Rear hole 45 Bottom 5 Second operating body 51 Operating Unit 52 Tail crown 53 Front inner circumference 54 Center inner circumference 55 Rear inner circumference 56 Second stage 6 Friction body 61 Protrusion 7 Rotating Member 8 magnets 81 N pole 82 S pole 9. Cylindrical body (ferromagnetic material) 10 mounting slots 11 projectiles

Claims

1. A writing body is accommodated inside a barrel so as to be movable in the front-to-rear direction, thermochromic ink is accommodated inside the writing body, a pen tip capable of ejecting the thermochromic ink is provided at the front end of the writing body, a first operating body movable in the front-to-rear direction protrudes from a side wall of the barrel, and the pen tip of the writing body can be made to appear and disappear from a front end hole of the barrel by sliding the first operating body forward, A thermochromic writing instrument containing a friction body made of a low-wear elastic material inside the barrel, which is capable of rubbing the handwriting of the thermochromic ink and thermally discoloring the handwriting with the frictional heat generated at the time, a second operating body at least partially protruding from the rear end of the barrel at the rear of the writing body and capable of operating the first operating body; The second operating body has the friction body at its front portion and is detachably attached to the barrel by magnetic force so as to be slidable back and forth along the axial direction.

2. A thermochromic writing instrument as described in claim 1, characterized in that a magnet is provided on either the barrel or the second operating body, and a ferromagnetic material that is attracted to the magnet is provided on the other.

3. A thermochromic writing instrument as described in claim 1 or 2, characterized in that when the second operating body is removed from the barrel, the second operating body can be attached and detached freely from the barrel by magnetic force even if the front-to-back direction of the second operating body is reversed.

4. The thermochromic writing instrument according to claim 3, characterized in that when the second operating body is attached to the barrel in a reversed front-to-back position, at least a portion of the friction body engaged with the first operating body protrudes outward from the barrel.

5. A thermochromic writing instrument as described in claim 3 or 4, characterized in that when the second operating body is attached to the barrel in a reversed front-to-back position, the operating body abuts against a regulating portion that regulates the forward movement of the operating body.

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